Ronin Son is the thirty-sixth episode of Bakugan Battle Planet.
Shun's cousin claims Hydorous as his intellectual property, causing The Awesome Ones to battle in order keep their friend Hydorous, but in the middle of the battle Shun finds a way of evolve Hydorous by tapping into the energy of the Mind Core Cell.
Shun decides he has to go back to Japan, he speaks with his father over the phone. Ichiro said Shun could stay in Los Volmos, but only to discover the secrets of Bakugan. Shun has no reason to stay in Los Volmos now that he has accomplished that mission. Ichiro sent Masato to bring him back, if Shun refuses then he will be cut off and will have no relation to his father or the Kazami family. Shun truly doesn’t want to go back, Dan, Wynton, and Lia decide they need to do something, they won’t let Masato get away with it. The AO go to Benton Dusk and ask if there is a way to draw energy from the Core Cell in order to evolve and beat Masato’s Serpenteze. Benton mentions the phenomenon of the glowing hexagon in the sky, it was very similar to the Great Collision, it likely has to do with the interaction between the Core Cell. Shun actually has been emailing his dad about how he loves living in Los Volmos, this is how his father knows about the Maze.
The AO then try to draw the energy of the Core Cell but fail once again, Shun talks to Hydorous about what he can do, he wants to stay here, but he can’t go against the Kazami family's decision. The next day Masato arrives to get Shun’s answer, he tells Shun he will make him come to his senses and initiates a brawl once again, this wakes up Dan, Lia, and Wynton. It’s a battle between Serpenteze vs. Hydorous, Fade Ninja, and Vicerox. Masato tells Shun that he wants to defeat Shun here today with his own hands, this will prove President Kazami that he is better, and he will take his place as the Kazami heir. Masato uses Hydro Blade and easily knocks back all three of Shun’s Bakugan, Dan. Lia, Wynton, and Lightning run to help Shun but are stopped by Toshi, Koda, and Keiko. Toshi uses Aquos Garganoid, Koda uses Pyrus Mantonoid, and Keiko uses Ventus Nobilious. The battle begins, but Ichiro’s bodyguards create a cage and trap Dan, Lia, Wynton, and Lightning so they can’t help Shun.
Masato believes it is right to beat Shun, he always had more talent and Shun shamed his own family and company in order to hang around with his “ridiculous” friends, Masato believes he’s the rightful successor. Serpenteze uses Flash Flood against Shun’s Bakugan but Fade Ninja and Vicerox step in to protect Shun and go back to ball form. Dan tells Masato that he doesn’t care about the business, Shun’s friendship is most important to them; the AO and their Bakugan try to break through the cage. Serpenteze and Hydorous clash, with Hydorous becoming weak, Shun realizes it’s clear - that his friends and his Bakugan are most important to him, yet the still lets his father and his Kazami family name holds him back. He won’t let Masato exploit Bakugan for-profit and insult his friends. Shun tells for Masato that he will fight for his friends and his Bakugan, he grabs a BakuCore and then feels a presence that is like the Core Cell, he throws a powered up BakuCore and creates an Aquos Evolution, evolving Hydorous into Hyper Hydorous.
Masato and Ichiro’s assistants are shocked Hydorous evolved, and the AO cheer Shun on. Serpenteze tries to use Fog Shield but the shield is easily broken, Masato uses Flash Flood and Shun uses Double Aquos Blast. Shun’s attack overpowers Serpentezes thanks to their new powers. Shun then tells Hydorous it's time to finish this and uses Hyper Hurricane Slash, finishing Serpenteze. Masato loses the battle and laughs, telling Shun that he will report the power of an evolved Bakugan to President Kazami, including the fact that Shun betrayed the Kazami Family. Later that day, Shun tries to call his father, but he won’t respond, his father has cut communication with him. Shun tells Dan that this is the path he has chosen and tells Lia to upload the video of Hydorous evolving online, risking his father getting mad. Shun wants to tell the world about the potential Bakugan have, the AO is a great team and this is what they do, so Lia uploads the video. Shun hopes his father will eventually understand. The AO will always stick together, so nothing will scare them.
- Dan (Drago), Wynton (Trox), and Lia (Pegatrix) vs. Toshi (Garganoid), Koda (Mantonoid), and Keiko (Nobilious) = No result
- Shun Kazami (Hydorous, Fade Ninja, and Vicerox) vs. Masato Kazami = Shun wins
- Dan Kouzo
- Wynton Styles
- Lia Venegas
- Shun Kazami
- Masato Kazami
- Ichiro Kazami
- Benton Dusk
- Hyper Hydorous